Cheers and Frasier were good though, and only had 11 seasons each. I still watch The Big Bang Theory but it started going downhill after season 3 when they all started getting girlfriends and it became another sitcom full of relationship drama.
The main 3 cast members all get $1million per episode and I guess now the rest of the main cast will want more too, so I expect season 12 to be the last. That's how long Two and a Half Men lasted and it was the same creator behind both.
It's Always Sunny in Philadelphia has been renewed until at least season 14 and I'm thankful for that. They even have less censorship now and threw out a fuck and at least 3 cunts a couple of episodes ago.